Preservation of rubber



Patented June 13, 1933 UNITED STATES PATENT "OFFICE 1m wrLiiIAMsoFwoonsrown, NEW JERSEY, ,A nARrHUR MOBBILLNEAIJ, or

WILMINGTON, DELAWARE, nssrenoits To I. DU 201w DE NEMOUBS 8; COMPANY, 1OF WILMINGTON, DEL WARE, A *eoafronnrron or DELAWARE 1 r EsEBVATIoN orRUBBER ll'o Drawing. Application filed Jiune 30, I lhis inyentionrelates to the preservation .ofr ubber and more particularlyto theincor- .poration of compounds in rubberwhich compounds retard thatdeterioration which rub 5 ber normally undergoes when subjectedto theaction of heat, light andoXidation. v 7

It is Well known that certaln substances, for j example, the secondaryaromatic amines,

possess thepoweiywhen incorporated in rub- 10 ber,of retarding thatdeterioration of the rubber Which is due to heat and oxidation.l-Ioweyer, these compounds have generally proved to be unsuitable forusein certain F types of white and light colored goods be cause of thefact that they discolor the rubber further object is to incorporate inrubber a class of compounds of theabove type which do not discolor therubber on exposure to light. Other and further objects are to pro- -videa new composition of@ matter and to advance the art. Other objects willappear hereinafter.

These objects may be accomplished according to the presentimention.which comprises incorporating in rubber acompoundwofthe type:

wherein R represents anaryl, substituted aryl or arallcyl radicalrXrepresents hydrogen or an alkyl or alkoxy radical; and Arepresents asubstituted orjunsubstituted amino @14 group. Theyarious significations.of Aniay be represented by the following radicals:

R1 i -N/ and ;-N=Ra 1932. Serial No. 620,308.

wherein R and R represent hydrogen, aryl, or aralkyl radlcals and Rrepresents an arallryl group connected to the nitrogen by adouble bondor a radical wherein the nitrogen forms part of a heterocyclic ring,such as pentamethylene or morpholyl. When A represents the radical: i

. l fRdl the complete formula will appear as follows:

. The term .aralkyl as'employed in the specification and claims may bedefined'as'an alkyl grouper radical having one or more of the hydrogenatoms thereof replaced by an arylbr substituted arylgroup or radical.

Compounds of this type are well known wand. methods of making themtogether with their properties are described byBettiGazet Betti GazettaChemicaltaliana,1901, 61. 31,

pounds} are also given in Organic Syntheses (1929 vol. 9, p. 60,published byJohn' Wiley .as ns.

Amongfthe compounds of this classwhich welhave found to be particularlyefl'ective for our purpose are the following:

Q hydrOXy-Lnaphthyl-phenylaminoqneth- Phenyl (benzylidene imino) 2hydroxy 1 naphthyl p-anisyl-amino- Phenyl- (benzylidene-imino) 2hydroxy-lnaphthyl-methane p-anisyl (pmethoxy-benzylideneimino)-2hydroxy-l-naphthyl-methane CHaO- 2-phenyl ethyl(3-phenyl-propylideneimino) -2-hydroxy-l-naphthyl-methane In order totest the effects of this type of compound by the change in physicalproperties of the rubber containing the same on aging, the followingstocks were prepared:

A A C 100 100 100 10 10 10 4 4 4 Diphenyl guanidine 1 1 1Phenyl-(benzylidene imino)2-hydroxy-1-naphthyl methane 2-phenylethy1-(3-phenyl propylidene imino)-2 hydroxy-l-naphthyl methane Thesestocks were then vulcanized to a comparable state of cure at 141 C. andtested by suspending them in the oxygen bomb at C. and 300 lbs. oxygenpressure per square inch for 48 hours. The effects of such treatment onthe physical properties of the stocks are given in Table II.

Table II Tensile Stock 22 5 5 after 6 aging In order to test thedeterioration retarding or inhibiting functions of these compounds thefollowing stocks Were prepared:

A B O D E Pale crepe 100 100 100 100 100 Zn oxide..- 3 3 3 V 3 3 Titan0x5O 50 50 50 50 Suliur 2 2 2 2 2 Thionex 0. 2 0. 2 O. 2 0. 2 0. 2

Z-hydroxy-l-naphthyl phenylamino methane l 2-hydroxy-1-naphthy1 pnisylamino methane 1 ydroxyl-naphthyl methane p-anisyl (p-methoxybenzylidene imino) 2-hydroxy-1-naphthy1 methane These stocks WerethenVulcanized at 120 C. to a comparable state of cure. They Were thensubjected to artificial aging by suspending them in a Bierer-Davis bombat? 0 C. and 300 lbs. oxygen pressure per square inch, until they Werecompletely deteriorated. The results of such tests appear in Table I.

Table I 7 Days in bomb Stock for complete deterioration A 7 B more than14 C more than 14 D e 13 E 12 Other compounds of this class which shouldbe given special consideration are 2-hydroxy -1.- naphthyl phenylpiperidyl methane Phenyl-2-hydroxy-l-naphthyl-phenyl-amino no-methane il @y Q 2-l1ydroXy-1-naphthyl phenyl morpholylmethane I \CHPCHZ/ rubberwhich comprises incorporating in the 2 hydroxy-7-methoxy-1naphthylphenylamino-methane OHaO Phenyl P 2 hydroxy-7-methyl- 1-naphthylbenzylamino-methane LME In the above examples, we havedisclosed theuse of one part of the deterioration inhibitor to 100 partsof rubber and also the incorporation of the inhibitors into the rubberprior to vulcanization. However, largeror smaller amountsof theinhibitor may be employed within a rather wide range. The particularamount of inhibitor employed depends largely upon the desire of themanufacturer and the conditions and characteristics of the rubber stockinwhich they are incorporated. Furthermore, these deteriorationinhibitors may also beincorporated into the rubber after vulcanizationby any of the well known methods of impregnation.

From the above examples, it will appear that we have found a new classof compounds which, when incorporated into rubber, efi'ectively retardthat deterioration of the rubber which is due to the action of light,heat and oxidation, that by incorporating these compounds into rubber weeffectively retard deterioration thereof, and the resulting productshave new and better properties than other previously known products of asimilar type.

While we have disclosed the use of certain specific compounds inspecific proportionsfln particular rubber stocks, itwill be apparem tothose skilled in the art that many other compounds within the class maybe'employed, the proportions may be widely varied and the compositionsof the stocks variously modified without departing from the spirit ofour invention. Accordingly, the scope of our invention is to be limitedsolely by the append ed claims construed as broadly as is permissible inview of the prior art.

We claim: 1. The method of preserving vulcanized rubber a small amountof a compound of the type: i

H It'll-A 2:. The method of preserving vulcanized rubberwhichcomprisesincorporating in the.

rubber a small amount of a compound of the type: a

. R-b-uk 3. The method of preserving vulcanized rubber which comprisesincorporating in the rubber a small amount of a compound of the type:

i l R1 i wherein R andR represent members of the group consisting ofhydro en and aryl, aralkyl and aralkylidene ra icals.

5. The method of preserving vulcanized rubber which comprisesincorporating in the rubber a small amount of a compound of the type:

wherein A represents a nitrogen containing heterocyclic radical.

6. The method of preserving vulcanized rubber which comprisesincorporating in the sic rubber a small amount of a compound of whereinA represents a nitrogen containing rubber a small amount of acompound'of wherein A represents a nitrogen containing the type:heterocyclic radical of the group consistin H of pentamethylene andmorpholyl radicals. 11. Vulcanized rubber having incorporated therein asmall amount of a compound of the type:

X i H i ETC-A orr wherein A represents a nitrogen containingheterocyclic radical of the group consisting of pentamethylene andmorpholyl radicals;

7. The method of preserving vulcanized rubber Which comprisesincorporating in the Vulcamzed rubber ha'vlng 111601130 rated therein asmall amount of a compound 1: the type: Oi the type.

v n R-(I3A 18. Vulcanized rubber having incorporated therein 'a smallamount of a compound of the'type:

wherein A represents a nitrogen containing 8. The method of preservingvulcanized H rubber whlch comprises 1ncorporat1ng 1n the c I '/R1 rubbera small amount of a compound of I the type: H OH wherein R represents amember of the group consisting of aryl, aralkyl, and substituted arylradicals and R and R represent members of the group consisting ofhydrogen and ar 1 arall' l and aralk dideie rac ical. heterocychcradical of thegroup consistlng y 3 l 1 9 of pentamethylene and morpholylradicals.

14. Vulcanized rubber having incorpo- 1 rated therein a sm ll (nous L 19. The method of PIGSBIVIIIO vulcanized a u of 1 col mp0 1nd b of thetype. rubber WhlCh comprlses incorporating 1n the H rubber a smallamount of a compound of the I /Ri yp I \R:

v H a I wherein R and R represent members of the group consisting ofhydrogen and aryl, aralkyl and aralkylidene radicals.

15.Vulca111Zed rubber having incorporated therein a small amount of acompound of the type:

wherein A represents a nitrogen containing heterocyclic radical.

10. The method of preserving vulcanized rubber which comprisesincorporating in the rubber a small amount of a compound of the type a vto; O 1

COM

wherein A represents a nitrogen containing heterocyclic radical.

" 16. Vulcanlzed rubber having incorporated therein a small amount of acompound of the type:

H lath wherein A represents a nitrogen containing heterocyclic radicalof the group consisting of pentamethylene and morpholyl radicals.

17 Vulcanized rubber having incorporated therein a small amount of acompound of the type:

wherein A represents a nitrogen containing heterocyclicradical.

18. Vulcanized rubber having incorporated therein a small amount of acompound of the wherein A representsa nitrogen containing heterocyclicradical of the group consisting of pentamethylene and morpholylradicals.

19. Vulcanized rubber having incorporated therein a smallamount of acompound of the type:

wherein A represents a nitrogen containing heterocyclic radical. a

20. Vulcanized rubber having incorporated therein a small amount of acompound of the type a type wherein A represents a nitrogen containingheterocyclic radical ofthe group consisting of pentamethylene andmorpholyl radicals.

21. Vulcanized rubber having incorporated therein a small amount ofZ-hydroxy-l-naphthyl phenyl-amino methane.

tures.

IRA WILLIAMS. ARTHUR MORRILL NEAL.

